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Environment Education पर्यावरण शिक्षण

Class 11 (Science, Commerce, Arts) · 5 chapters · 5 with notes

📘 Official textbook PDF

English medium · free PDF, ebalbharati.in

Chapters

  1. 1Environment and Sustainable DevelopmentNotes
  2. 2EcosystemsNotes
  3. 3BiodiversityNotes
  4. 4Natural ResourcesNotes
  5. 5DisastersNotes

Class 11 (Science, Commerce, Arts) · Environment Education · Chapter 1

Environment and Sustainable Development

Quick summary

This chapter introduces the environment as a subject that links many sciences. It explains the spheres of the earth, the scope and importance of environmental studies, the national and international organisations working for the environment, people who contributed to its protection, and the idea of sustainable development.

Key points

  • Environment includes everything around us, living (biotic) and non-living (abiotic), and their interactions.
  • It is interdisciplinary: it draws on biology, chemistry, physics, geography, economics, sociology, law and engineering.
  • Spheres of the earth: atmosphere (air), lithosphere (crust, soil, rocks), hydrosphere (water) and biosphere (zone where life exists).
  • Atmospheric layers: troposphere (weather), stratosphere (ozone layer, the "protective layer" absorbing UV rays), mesosphere, thermosphere, exosphere.
  • Environmental degradation is damage to the environment from human activities such as pollution, deforestation and over-use of resources.
  • The UN Conference on the Human Environment was held at Stockholm, 5–16 June 1972; World Environment Day (5 June) marks it.
  • Organisations: Botanical Survey of India (1890), IUCN (5 October 1948), WWF (1961, Switzerland; logo giant panda), UNEP, Bombay Natural History Society (1883), Central Pollution Control Board (1974, under the Water Act), Maharashtra Pollution Control Board (1970), Wildlife Institute of India (1982), ENVIS.
  • People: Salim Ali, the "Birdman of India", helped save Silent Valley; Sunderlal Bahuguna led the Chipko movement; M. C. Mehta, environmental lawyer, won cases on cleaning the Ganga; M. S. Swaminathan, father of the Green Revolution; Amrita Devi and the Bishnois gave their lives to save Khejri trees in 1730.
  • Sustainable development meets present needs without harming future generations' ability to meet theirs. India adopted the concept after the 1972 Stockholm Conference; the Rio Earth Summit (1992) gave Agenda 21.
  • The UN Decade of Education for Sustainable Development began in 2005 and stressed education as essential for sustainability.

Important terms

  • Biotic / abiotic – living / non-living parts of the environment.
  • Biosphere – part of the earth where life exists.
  • Ozone layer – layer in the stratosphere that absorbs harmful ultraviolet rays.
  • Environmental degradation – damage to the environment by human activity.

Key facts

Organisation / eventYear
BNHS1883
IUCN1948
WWF1961
Stockholm Conference1972
CPCB1974

5 important questions

Q1. Why is environmental studies called interdisciplinary?

Because understanding and solving environmental problems needs knowledge from many subjects such as biology, chemistry, geography, economics, law and engineering.

Q2. What is the logo of WWF?

The giant panda.

Q3. Explain the four spheres of the earth.

Atmosphere is the layer of air; lithosphere is the solid crust with rocks and soil; hydrosphere includes all water bodies; biosphere is the zone where these meet and life exists.

Q4. Write about the contribution of any two environmentalists.

Salim Ali studied birds across India and helped save Silent Valley. Sunderlal Bahuguna led the Chipko movement where villagers hugged trees to stop felling.

Q5. What is sustainable development? Why is it needed?

Development that meets today's needs without harming future generations. It is needed because resources are limited and unchecked growth causes pollution and loss of biodiversity.

Exam tip

Prepare a table of organisations with their year and work; match-the-pair questions are common.

📘 Official textbook PDF

English medium · free PDF, ebalbharati.in
Ecosystems →

Class 11 (Science, Commerce, Arts) · Environment Education · Chapter 2

Ecosystems

Quick summary

An ecosystem is a community of living organisms interacting with each other and with their non-living surroundings. This chapter covers the scope of ecology, the structure and functions of an ecosystem, its types, energy flow and nutrient cycles, ecosystem services, interactions between species and ecological succession.

Key points

  • Ecology is the study of relationships between organisms and their environment. The part of the earth that supports life is the biosphere.
  • Structure: abiotic components (sunlight, water, air, soil, minerals, temperature) and biotic components — producers (green plants), consumers (herbivores, carnivores, omnivores) and decomposers (bacteria, fungi).
  • Producers make food by photosynthesis; decomposers break down dead matter and return nutrients to the soil.
  • A food chain shows who eats whom (grass → deer → tiger); interlinked food chains form a food web. Each step is a trophic level.
  • Only about 10% of energy passes from one trophic level to the next (10% law); the rest is lost as heat. So the pyramid of energy is never inverted.
  • Grazing food chain starts with green plants; detritus food chain starts with dead organic matter.
  • Nutrients move in biogeochemical cycles (carbon, nitrogen, water, phosphorus).
  • Types: terrestrial (forest, grassland, desert) and aquatic (freshwater ponds, lakes, rivers; marine; estuaries).
  • Ecosystem services: provisioning (food, water, timber), regulating (climate, flood control, pollination), cultural (recreation, spiritual), supporting (soil formation, nutrient cycling).
  • Species interactions: competition, predation, parasitism (Cuscuta on a host plant), mutualism (lichen: alga + fungus, both benefit), commensalism (epiphyte orchid Vanda on a tree: one benefits, other unaffected).
  • Ecological succession is the gradual replacement of one plant community by another. Primary succession starts on bare rock; secondary on land that once had vegetation. Pioneers (lichens, mosses) come first; the stable final community is the climax.

Important terms

  • Trophic level – position of an organism in a food chain.
  • Food web – network of interconnected food chains.
  • Pioneer species – first organisms to colonise a bare area.
  • Climax community – stable, self-maintaining final stage of succession.

Key facts

InteractionEffect on species A / BExample
Mutualism+ / +lichen
Commensalism+ / 0Vanda orchid on tree
Parasitism+ / −Cuscuta on host
Predation+ / −tiger and deer

5 important questions

Q1. What are decomposers? Give examples.

Organisms like bacteria and fungi that break down dead plants and animals and return nutrients to the soil.

Q2. Why is the pyramid of energy never inverted?

Because only about 10% of energy passes to the next level and the rest is lost as heat, so energy always decreases upward.

Q3. Explain the structure of an ecosystem.

Abiotic components include sunlight, air, water, soil and minerals. Biotic components are producers, consumers and decomposers, linked by food chains.

Q4. Explain any three types of species interactions.

Mutualism: both partners gain (lichen). Commensalism: one gains, other unaffected (epiphytic orchid). Parasitism: parasite gains, host is harmed (Cuscuta).

Q5. What is ecological succession? Describe its stages.

Gradual change of plant communities in an area. Bare rock → lichens and mosses (pioneers) → grasses → shrubs → trees (climax).

Exam tip

Draw a labelled food web and an energy pyramid; diagram questions are common in this chapter.

📘 Official textbook PDF

English medium · free PDF, ebalbharati.in
← Environment and Sustainable DevelopmentBiodiversity →

Class 11 (Science, Commerce, Arts) · Environment Education · Chapter 3

Biodiversity

Quick summary

Biodiversity is the variety of all living organisms — plants, animals and microbes — and the ecosystems they form. This chapter explains levels and values of biodiversity, India as a mega-diversity nation, threats to biodiversity, man–wildlife conflict and methods of conservation.

Key points

  • Biodiversity is the result of about 3000 million years of evolution. Examples of richness: over 20,000 kinds of ants, about 3,00,000 kinds of beetles, about 20,000 kinds of orchids.
  • Three levels: genetic diversity (variation within a species, e.g. many rice varieties; Warlis grow about 15 varieties of crops), species diversity (number of species in an area) and ecosystem diversity (forests, grasslands, wetlands, deserts).
  • Direct values: consumptive (food, fodder, firewood used locally) and productive (sold commercially: timber, gum, medicines, fibre, biofuels like Jatropha and Karanj). About 25% of prescription drugs in developed countries come from plants.
  • Indirect values: ecological (oxygen, climate, water flow, pollination, soil fertility), social, ethical (right of all species to live; sacred trees like peepal, banyan, tulsi), aesthetic (ecotourism) and option value (possible future uses).
  • India is one of 17 mega-diversity nations and has parts of four biodiversity hotspots: the Himalaya, Indo-Burma, Western Ghats–Sri Lanka and Sundaland (Nicobar Islands).
  • Hotspots are areas with very high species richness, many endemic species and high threat; the textbook lists 35 worldwide.
  • Threats: habitat loss and fragmentation, poaching and illegal trade, pollution, invasive species, over-exploitation, climate change.
  • Man–wildlife conflict happens when animals (leopards, elephants, wild boar) enter farms and villages as forests shrink, causing loss of crops, cattle and lives on both sides.
  • Conservation: in-situ (in natural habitat — national parks, wildlife sanctuaries, biosphere reserves, sacred groves) and ex-situ (outside habitat — zoos, botanical gardens, seed banks, gene banks, tissue culture).
  • The IUCN Red List classifies species by threat: extinct, critically endangered, endangered, vulnerable and others.

Important terms

  • Endemic species – species found only in one particular region.
  • Hotspot – species-rich region with high endemism under serious threat.
  • In-situ conservation – protecting species in their natural home.
  • Ex-situ conservation – protecting species outside their natural home.

Key facts

ItemDetail
Mega-diversity nations17 (India is one)
Hotspots in India4
Hotspots worldwide (textbook)35
Medicinal plants used in Western Ghatsabout 2000

5 important questions

Q1. Define biodiversity.

The variety of living organisms — genes, species and ecosystems — found in an area or on the earth.

Q2. Name the biodiversity hotspots in India.

Himalaya, Indo-Burma, Western Ghats–Sri Lanka and Sundaland (Nicobar Islands).

Q3. Explain the three levels of biodiversity.

Genetic: differences within one species. Species: variety of species in a region. Ecosystem: variety of habitats like forests, wetlands and deserts.

Q4. What are the threats to biodiversity?

Habitat destruction, poaching and illegal wildlife trade, pollution, invasive alien species, over-use of resources and climate change.

Q5. Differentiate between in-situ and ex-situ conservation.

In-situ protects species in their natural habitat, e.g. national parks and sanctuaries. Ex-situ protects them outside, e.g. zoos, botanical gardens and seed banks.

Exam tip

Classify values of biodiversity in a tree diagram (direct and indirect) — it makes long answers easy to score.

📘 Official textbook PDF

English medium · free PDF, ebalbharati.in
← EcosystemsNatural Resources →

Class 11 (Science, Commerce, Arts) · Environment Education · Chapter 4

Natural Resources

Quick summary

Natural resources are materials and energy from nature that people use — water, forests, food, land and minerals. This chapter classifies them, explains each resource, the problems of over-use, and how they can be used sustainably, with the example of Hiware Bazar village in Maharashtra.

Key points

  • Renewable resources are replenished by nature (water, forests, wildlife); solar and geothermal energy are called perpetual. Non-renewable resources are not easily replaced (coal, petroleum, natural gas, minerals); some are recyclable (metals), some are not (fossil fuels, uranium).
  • About 97% of the earth's water is in oceans; only about 3% is fresh, and most of that is locked in ice. Groundwater forms a small but important part. Plants and animals contain 60–65% water.
  • Groundwater levels have fallen in about half of Maharashtra because of over-pumping.
  • Hiware Bazar (Ahmednagar district, rainfall under 400 mm) used watershed work, contour bunds, about 660 water-harvesting structures and forest regeneration under the Adarsh Gaon Yojana (from 1994). Wells rose from 97 to 217, milk from 150 to 4,000 litres a day and poverty fell sharply.
  • Forests give timber, fuel, fodder, medicines and also control climate, soil erosion and floods. Deforestation is caused by farming, mining, dams, roads and fuelwood needs.
  • Food resources: the Green Revolution raised yields but caused over-use of fertilisers, pesticides and water, soil salinity and loss of crop varieties.
  • Land degradation includes soil erosion, waterlogging, salinity and desertification; contour farming, terracing, afforestation and crop rotation help.
  • Mineral mining causes deforestation, land damage, water and air pollution and displacement of people; recycling metals and reclaiming mined land reduce harm.
  • Sustainable use: use renewables, reduce wastage, recycle, conserve water and forests, and involve local communities.

Important terms

  • Renewable resource – resource that nature replaces over a short time.
  • Non-renewable resource – resource that takes millions of years to form and can be exhausted.
  • Aquifer – underground rock layer that stores groundwater.
  • Desertification – turning of fertile land into desert-like land.

Key facts

Water on earthShare
Oceansabout 97.3%
Ice and glaciersabout 2.2%
Groundwaterabout 0.5%
Rivers and lakesvery small fraction

5 important questions

Q1. Distinguish between renewable and non-renewable resources.

Renewable resources are replaced naturally, like water and forests. Non-renewable resources such as coal and petroleum are limited and cannot be replaced in a human lifetime.

Q2. What percentage of the earth's water is fresh water?

Only about 3%, and most of it is frozen in ice caps and glaciers.

Q3. What are the effects of deforestation?

Soil erosion, floods, loss of wildlife habitat and biodiversity, less rainfall, climate change and hardship for forest-dependent people.

Q4. Write a note on Hiware Bazar.

A drought-prone village in Ahmednagar that, under Popatrao Pawar's leadership and the Adarsh Gaon Yojana, built bunds and water-harvesting structures and regenerated forest. Wells, irrigation, grass, milk output and incomes rose greatly.

Q5. How can natural resources be used sustainably?

Use renewable energy, harvest rainwater, plant trees, recycle metals and paper, avoid wastage and let communities manage local resources.

Exam tip

Use Hiware Bazar as a ready Maharashtra example in any answer about water or resource conservation.

📘 Official textbook PDF

English medium · free PDF, ebalbharati.in
← BiodiversityDisasters →

Class 11 (Science, Commerce, Arts) · Environment Education · Chapter 5

Disasters

Quick summary

A disaster is a sudden event that causes great loss of life, property and environment, beyond the ability of the affected community to cope. This chapter explains types of disasters, natural and man-made disasters with Maharashtra examples, their effects, do's and don'ts for safety, and the disaster emergency kit.

Key points

  • Hazard is a possible threat; it becomes a disaster when it strikes vulnerable people and causes heavy loss.
  • Types: natural (earthquake, flood, cyclone, drought, landslide, tsunami, lightning) and man-made (fire, industrial or chemical accidents, gas leaks, building collapse, stampede, war, terrorism).
  • In the last twenty years disasters have killed about three million people worldwide and affected about one billion.
  • Earthquakes in Maharashtra: Koyna (11 December 1967, magnitude 6.5) and Latur (30 September 1993, 3:56 a.m., magnitude 6.4, shallow 12 km focus, very high deaths). Koyna region of Satara has the most tremors. Bhuj, Gujarat (26 January 2001) was another major quake.
  • During an earthquake: drop, cover and hold under a strong table; stay away from glass and heavy objects; if outdoors, move to open ground away from buildings and wires.
  • Floods come from heavy monsoon rain, cyclones and storm surges; Mumbai was paralysed by floods on 26 July 2005. Don't walk near river banks, keep away from electric wires, move to higher ground.
  • Cyclones form around low pressure areas with strong winds and heavy rain; coastal Maharashtra faces cyclone risk. Keep torches, dry food and wooden boards ready.
  • Droughts and landslides (e.g. Malin, Pune district, 2014) also hit Maharashtra.
  • Effects: deaths and injuries, homelessness, disease, damage to roads, power and water supply, crop and livestock loss, economic and psychological shock.
  • After the Latur earthquake a monitoring centre was set up; India's Disaster Management Act (2005) created the National Disaster Management Authority (NDMA).
  • Disaster emergency kit: drinking water, dry food, first-aid box, torch and batteries, radio, whistle, important documents in a waterproof bag, some cash, medicines, clothes, phone charger.

Important terms

  • Hazard – a natural or man-made threat that may cause harm.
  • Disaster – serious event causing widespread loss that a community cannot handle alone.
  • Richter scale – scale used to measure the magnitude of earthquakes.
  • Emergency kit – bag of essential items kept ready for disasters.

Key facts

DisasterDateDetail
Koyna earthquake11 Dec 1967magnitude 6.5
Latur earthquake30 Sep 1993magnitude 6.4
Bhuj earthquake26 Jan 2001Gujarat
Mumbai floods26 Jul 2005city paralysed

5 important questions

Q1. Differentiate between a hazard and a disaster.

A hazard is a possible threat; a disaster is when that threat actually causes heavy loss to a vulnerable community.

Q2. When did the Latur earthquake occur and what was its magnitude?

On 30 September 1993, magnitude 6.4 on the Richter scale.

Q3. What should you do during an earthquake?

Drop, take cover under a strong table and hold on; keep away from windows and heavy objects; if outside, go to open ground away from buildings, trees and power lines.

Q4. What should a disaster emergency kit contain?

Water, dry food, first-aid kit and medicines, torch with batteries, radio, whistle, documents in a waterproof cover, cash, clothes and phone charger.

Q5. Explain the effects of disasters.

Loss of life and injuries, homelessness, spread of disease, damage to infrastructure and crops, economic loss and mental trauma.

Exam tip

Learn the do's and don'ts for each disaster; practical "what will you do" questions are common.

📘 Official textbook PDF

English medium · free PDF, ebalbharati.in
← Natural Resources